From 12e1284a67e5e3404c704c3f864749fd9f04c7c4 Mon Sep 17 00:00:00 2001
From: Tony Cook <tony@develop-help.com>
Date: Wed, 7 Aug 2019 14:58:14 +1000
Subject: [PATCH] PerlIO::Via: check arg is non-NULL before using it.
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I can't find any code in core that ends up calling the _pushed handler
with arg == NULL, but PerlIO_push() is API, and there might be
CPAN or DarkPAN code out there that does, escpecially since there's
a check for arg being non-NULL further down.

CID 169261.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 ext/PerlIO-via/via.xs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ext/PerlIO-via/via.xs b/ext/PerlIO-via/via.xs
index d91c6855fc..8456242bc0 100644
--- a/ext/PerlIO-via/via.xs
+++ b/ext/PerlIO-via/via.xs
@@ -134,8 +134,8 @@ PerlIOVia_pushed(pTHX_ PerlIO * f, const char *mode, SV * arg,
 {
     IV code = PerlIOBase_pushed(aTHX_ f, mode, Nullsv, tab);
 
-    if (SvTYPE(arg) >= SVt_PVMG
-		&& mg_findext(arg, PERL_MAGIC_ext, &PerlIOVia_tag)) {
+    if (arg && SvTYPE(arg) >= SVt_PVMG
+        && mg_findext(arg, PERL_MAGIC_ext, &PerlIOVia_tag)) {
 	return code;
     }
 
-- 
2.21.0